What is the recommended dose of aspirin (acetylsalicylic acid) for daily prophylaxis?

Recommended Dose of Aspirin for Daily Prophylaxis

The recommended dose of aspirin for daily prophylaxis is 75-100 mg, as this range provides effective antithrombotic protection while minimizing gastrointestinal side effects. 1

Optimal Dosing Based on Clinical Context

General Cardiovascular Prophylaxis

• 75-100 mg daily is the recommended dose for long-term prevention of serious vascular events in high-risk patients 1
• This dose range provides sufficient inhibition of platelet cyclooxygenase-1 (COX-1) to prevent thrombotic events 1
• Higher doses (>100 mg) do not provide additional antithrombotic benefit but increase the risk of bleeding complications 1

Specific Clinical Scenarios

• For patients with SLE who are pregnant or considering pregnancy, 81 or 100 mg daily is conditionally recommended, beginning in the first trimester 1
• For women >65 years of age at higher cardiovascular risk, 81 mg daily or 100 mg every other day is recommended for stroke prevention 1
• For patients with antiphospholipid syndrome (APS), low-dose aspirin (81-100 mg) is used in combination with prophylactic-dose heparin 1

Evidence Supporting Low-Dose Regimens

Efficacy Considerations

• The Antithrombotic Trialists' Collaboration analysis showed no convincing evidence that higher doses (>100 mg) are more effective than lower doses (75-100 mg) in reducing vascular events 1
• Some evidence suggests that doses as low as 75 mg/day are effective for secondary prevention in stable coronary artery disease 1
• The CURRENT-OASIS 7 trial demonstrated that 75-100 mg/day was as effective as 300-325 mg/day for prevention of stroke, MI, or cardiovascular death 1

Safety Considerations

• Gastrointestinal side effects of aspirin are dose-dependent, with lower rates of bleeding at doses of 75-100 mg/day 1
• The CURE trial showed that aspirin 100 mg/day alone or with clopidogrel had lower rates of major bleeding than 200 mg/day 1
• The CURRENT-OASIS 7 trial confirmed less GI bleeding with 75-100 mg/day compared to 300-325 mg/day 1

Special Considerations

Aspirin with Ticagrelor

• When used with ticagrelor, the recommended maintenance dose is specifically 81 mg daily 1
• Higher doses of aspirin (>100 mg) may decrease the effectiveness of ticagrelor and increase bleeding risk 1

Acute Coronary Syndromes

• In situations requiring immediate antithrombotic effect (such as acute coronary syndromes), a loading dose of 160-300 mg should be given initially, followed by the lower maintenance dose of 75-100 mg daily 1

Common Pitfalls to Avoid

• Using doses >100 mg for long-term prophylaxis increases bleeding risk without additional antithrombotic benefit 1
• Alternate-day dosing (100 mg every other day) produces less consistent platelet inhibition than daily dosing (81 mg daily) 2
• Failure to adjust aspirin dosing when adding other antithrombotic agents (particularly important with ticagrelor) 1
• Using the same dose for all clinical scenarios without considering the specific vascular bed at risk 3

In conclusion, the 75-100 mg daily dose range provides the optimal balance between efficacy and safety for most patients requiring aspirin for cardiovascular prophylaxis, with specific dose adjustments needed for certain clinical scenarios and combination therapies.